PESHAWAR, Pakistan — Suspected Taliban fighters hijacked trucks carrying Humvees and other supplies for U.S.-led troops in Afghanistan, authorities said Tuesday after a brazen attack near the Khyber Pass that underscored the militants' grip across key mountain strongholds.

The assault highlighted the vulnerability of a vital supply route for the 65,000 U.S. and NATO forces battling a resurgent Taliban in landlocked Afghanistan. A significant amount of supplies for the Western forces go through Pakistan.

Attacks on convoys carrying food, fuel and other supplies are common on the road. But Monday's raid was especially large and well-organized. It also could further strain U.S.-Pakistani relations over rooting out Taliban and al-Qaida militants along the border, which remain entrenched despite military offensives and U.S. missile strikes.

Some 60 masked militants blocked the route at several points before overpowering the convoy, said Fazal Mahmood, a government official in Khyber tribal region. He identified the attackers as members of Pakistan's Taliban movement.

Security forces traded fire with the gunmen, but were forced to retreat, he said. The militants took about 13 trucks along with the drivers, who were believed to be Pakistani.

Hunting for the perpetratorsA U.S. military spokesman in Afghanistan confirmed the thefts late Tuesday.

"There were some U.S. military materials that were taken — Humvees and water tank trailers," said Maj. John Redfield.

Later Monday, a separate group of insurgents halted a truck carrying what appeared to be a NATO jeep, setting the military vehicle on fire, Mahmood said. NATO officials could not immediately be reached for comment on that incident.

In the past, U.S. and NATO officials have played down their losses along the pass.

But earlier this year, NATO said it was trying to reduce its dependence on the route by negotiating with Russia and other nations to let it truck "non-lethal" supplies to Afghanistan through Central Asia.

Security forces, backed by helicopter gunships, hunted for the missing trucks and drivers. The military said late Tuesday it had recovered some of the stolen materials but would not specify what.

"We are using all resources to trace and recover the hijacked trucks, some of which were carrying vehicles for the allied forces in Afghanistan," Mahmood said.

Dangerous routeMost of the supplies for U.S. and other foreign troops in Afghanistan arrive by ship at Pakistan's port of Karachi in unmarked containers. They are then taken by colorfully decorated trucks to places like Bagram Air Base, north of Kabul, the Afghan capital.

NATO and U.S. officials have declined to say if the trucks carry weapons and ammunition. They have in the past suggested that ordinary criminals — not an orchestrated campaign by militants — are the main problem.

The Khyber Pass, a stretch of about 30 miles, has long been an important trade route and militarily strategic area traversed for centuries by armies, from Moghul warriors to British colonial forces. It abuts the main northwestern Pakistan city of Peshawar.

In a bid to eliminate militancy in the border region, the U.S. has stepped up unilateral missile strikes there, a move condemned by Pakistani leaders who say it only deepens anti-American feelings among civilians.

Pakistani President Asif Ali Zardari was headed to the United States Tuesday for a U.N. conference on interfaith relations. He was expected to broach the subject of the missile strikes with U.S. officials.

Suicide attacks
Pakistan's prime minister, Yousuf Raza Gilani, issued a statement after a meeting Tuesday with a U.S. congressional delegation saying there was a "need for restoration of trust" between the two nations and that there must be "complete respect for Pakistan's territorial integrity."

Pakistan has pursued its own military offensives against insurgents, including ones in the Swat Valley and the Bajur tribal region. The U.S. has praised the operations, but the militants have staged a wave of suicide attacks, apparently in retaliation.

A suicide bomber blew himself up Tuesday outside a stadium hosting athletes from around the country, killing at least three people and wounding 17 while narrowly missing some top government leaders, officials said.

The bomber struck outside the main gate of the Peshawar Sports Complex, which was decked with lights for the closing ceremony of the Inter-Provincial Games. Officials had promoted the games as a way to improve the northwest's violent image.

The province's information minister, Mian Iftikhar Hussain, said he was just a few feet away from the site of the explosion when it happened, and that the province's governor had left the scene only 15 minutes before.

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